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Will my RB30 hit my bonnet?


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Hey guys,

just wondering if my Rb30 is going to hit the bonnet on my 240z, I am going to run the single cam for a while until I can afford the RB26 head. I'm going to use the castlemain rod shop engine mounts and just wondering if anyone can tell me if the intake is going to hit the bonnet, even thought the rocker cover might?

Saw a custom intake for the single cam head on ebay which was just a box that bolts onto the bottom half of the intake, it sat at the same height as the rocker cover but they go for about $400 and I would prefer the use the stock intake for now if I can get away with it. If I needed to use a custom jobby I will just get one made up (gotta love RAAF workshops). Any thoughts would be helpful.

Cheers. Nick

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Hey guys,

just wondering if my Rb30 is going to hit the bonnet on my 240z, I am going to run the single cam for a while until I can afford the RB26 head. I'm going to use the castlemain rod shop engine mounts and just wondering if anyone can tell me if the intake is going to hit the bonnet, even thought the rocker cover might?

Saw a custom intake for the single cam head on ebay which was just a box that bolts onto the bottom half of the intake, it sat at the same height as the rocker cover but they go for about $400 and I would prefer the use the stock intake for now if I can get away with it. If I needed to use a custom jobby I will just get one made up (gotta love RAAF workshops). Any thoughts would be helpful.

Cheers. Nick

 

I'm not far along enough in my build to help you, but there is someone on this board with an RB30DETT that's in the works, maybe he'll chime in. :)

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From what I can see on pics, (never seen a rb30 head in real life, just the blocks) with the boxy valve cover and the intake over it, it might not clear but then again, my RB25 with the over the head intake does fit.

 

Why not take the flange of your intake and build one yourself for the time being???

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The DOHC cam belt cover is fairly boxy; I have my motor lowered ~13mm; the cam belt cover is showing slight rub marks. SOHC is a tad smaller so you may be in luck.

 

Drop a nice cam in the SOHC and tidy up the head; they actually perform pretty damn well.

The problem is they are prone to cracking. :(

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I recall seeing on another thread with a pic of the Castlemain mounts next to someone else's and the Castlemain looked like they would mount the engine lower. Check with some of the Oz Zed forums and see if this question has been answered there before.

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I was going to add to this...

 

If the RB25 has a 60 mm pipe floating over the valve cover, and the RB30 is only 38 mm taller, if you moved the crossover pipe, you would have about 22 mm of clearance, plus what was there with the RB25.

 

This is assuming you have an RB25 head on the RB30 block.

 

makes sense, no?

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i've got a standard RB30ET in my 240Z,the mounts were custom made and are as low as you could get...so not sure about the CMRS ones

the point with the least clearance is the front corner of the intake plenum which fouls the bonnet by about 5mm

you may get away with canting the engine over by adjusting the mounts but i simply put a 10mm alloy spacer between the crossmember and the body effectively giving me 10mm more clearance,it worked well and i have not had any adverse effects(not that i expected any)

i am about to put in a new (++hp) motor and switching to an auto so will take the spacers out as i have a custom plenum and extractor manifold

i will be selling the complete turbo engine(T3 turbo and motor done less than 2000km since rebuild)/box/mandrel bent exhaust/radiator/tailshaft/intercooler/wiring loom/ecu(i used a wolf 3d and custom loom but have the std uncut VLT setup to go)

 

i am sticking to the SOHC head,they are not prone to cracking if you have a recycling system to ensure the coolant water remains free of air bubbles/cavitation,they are cheap(just got a free one),plentiful,you dont need multi coils(unreliable),aftermarket cams are cheap and plentiful,bit of porting makes a world of difference,not quite as torquey as DOHC but SOHC has more than you can get to the pavement in a Z,cams for DOHC heads are outrageously expensive

 

anyhow let me know if i can be of any further assistance

regards

paul

RB30ET006.jpg

RB30ET005.jpg

RB30ET004.jpg

RB30ET003.jpg

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Thanks very much to all you guys,

Paul you are the only person I can find that has actually kept the SOHC, I'm doing my car up for the missus and don't want her to kill herself so I'm keeping the engine pretty standard, as you said good porting and a nice cam and your set.

Thanks for the pics too, was awsome to finally see what mine will look like, your idea with the spacer in the crossmember sounds like it will solve my problems if they arise and I think I mite make a flatter wider custom jobby anyway. Couldn't help but notice the holden rocker cover, hahah nice.

Cheers. Nick

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